Although ethanol is commonly regarded as an anxiolytic, its administration mimics many actions of stress that involve activation of the hypothalamic-pituitary-adrenal axis (HPAA). An understanding of the effect of ethanol on this axis requires an appreciation of the central and peripheral regulatory factors and their interactions, which constitute the HPAA. Intimately involved in the homeostasis of the HPAA are several neuropeptides of brain origin [vasopressin and corticotropin-releasing hormone (CRF)] and pituitary origin [B-endorphin (BE) and adrenocorticotropin]. The long range goal of our research is to understand the role of alcohol in modifying the physiological functions of CRF and BE, neuropeptides associated with stress, in rat peripheral tissues. Since occupancy of high-affinity binding sites on target tissue membranes is known to initiate the physiological actions of neuropeptides, it was necessary to define optimal binding conditions for CRF and BE, as well as their peripheral target tissues, prior to examining ethanol-membrane perturbation. We have 1) identified, using 125I-rCRF, specific binding sites for CRF in various rat peripheral tissues and bovine chromaffin cells in culture and 2) established that occupancy of the CRF binding sites at least in rat adrenal membranes and bovine chromaffin cells, activates the adenylate cyclase/cAMP system. Furthermore, we have also identified using 125I-human BE, specific binding sites for BE in various rat peripheral tissues and established that occupancy of the BE binding sites at least in rat hepatic membranes activates the adenylate cyclase/cAMP system. Furthermore, in vitro exposure of various peripheral tissue membranes to varying concentrations of alcohol produced dose-related biphasic alterations in BE and CRF binding.